Hi Karen,
It is great that you are thinking about all of this for your dogs. Dental health is so incredibly important! While I cannot comment on your cost question, I can give you some general information about dental assessments and cleaning. A comprehensive oral health assessment and treatment (a.k.a. “COHAT” as we vets prefer to call these procedures) in pets must be done under general anesthesia. Pre-anesthetic bloodwork is certainly helpful and important before anesthesia. This information can help guide your veterinarian in selecting the most appropriate anesthetic protocol for your dog and ensures that all is well in terms of organ function before proceeding. In general, the earlier you can intervene (i.e. before there is significant periodontal disease), the better. Having a regular teeth cleaning in dogs performed and dental assessments, coupled with home care, which includes brushing (most important!), can help prevent the need for tooth extractions and extensive oral surgery in the future. I hope this gives you some direction.
Wishing you all the best with your dogs!
Dr. Kim Hester